Portion of an electron microscope



FIG. 1 is a front, top and right side perspective view of a portion of an electron microscope showing our new design;

FIG. 2 is a front elevational view thereof; the rear view is not part of the claimed design;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a right side elevational view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof; and,

FIG. 8 is a front, top and right side perspective view thereof shown in an opened positioned; the front, top and left side perspective view of the claimed design (shown in solid lines) is a mirror image of the claimed design as shown in FIG. 8.

The broken lines shown are for illustrative purpose and form no part of the claimed design. 

We claim the ornamental design for a portion of an electron microscope, as shown and described. 